Protecting wounds and animal skin from damage by environment, abrasion, wind, dirt, water, insect bites, etc. has been difficult. Most treatments are ineffective or require replacement frequently and may aggravate the conditions present. U.S. Pat. No. 5,192,536, issued to Huprich, covered a successful method and composition for coating a wound with polyether polyurethane. Polyether polyurethane dissolved in tetrahydrofuran provides a solution that can be applied to animal skin and dries rapidly to an elastic film that is vapor permeable, waterproof, wind proof, dirt proof, insect proof, and presents a barrier to bacteria. This film protects the skin from further damage during the healing process or exposure. This composition is useful and overcomes most of the problems inherent with conventional treatments.
Adhesion time is a factor which affects the efficacy of skin protectants. It is also important that the method of application provide complete rather than partial coverage of the area sought to be protected.
The invention of the parent case (Ser. No. 08/644,009) describes a polyether polyurethane composition dissolved in tetrahydrofuran (THF) which includes benzoin film or benzoin gum (hereinafter referred to as "benzoin/THF skin protectant"). The benzoin gum presents a patentable improvement over prior art skin protectants. First, the benzoin gum almost doubles the adhesion time of the polyether polyurethane composition to the affected skin area. Further, the benzoin gum converts a previously spreadable solution of polyether polyurethane to a composition suitable for dipping body extensions and limbs, thereby improving the ability of the composition to coat affected skin areas completely. An example of a preferred benzoin/THF skin protectant in accordance with the parent application is set forth as follows:
100 parts tetrahydrofuran PA0 10 parts polyether polyurethane PA0 5 parts benzoin gum
The amount of benzoin included in the composition can be adjusted to allow for more effective coverage of the desired surface area as necessary. The composition can be applied by a variety of methods including dipping, spraying, spreading, and wiping.
The benzoin/THF skin protectant may be used for a variety of skin protection purposes. It is especially useful as a teat dip for the prevention of mastitis. Up to 40-50% of intramammary infections are contracted during a cow's dry or non-lactating period, with the greatest percentages of these infections occurring during the first and last two weeks of the dry period. At these times, the mammary gland is in a transitional state: immunological factors are preoccupied or suppressed, milk is no longer being flushed from the gland, and increased mammary pressure distends the teat, thus allowing for easier bacterial penetration through the streak canal. The primary goal for mastitis control during the dry period is to minimize bacterial exposure on teat ends. Due to its long adhesion time and coverage, the benzoin skin protectant is useful for the prevention of mastitis during the dry cow period.
It would also be desirable to incorporate a germicide in the benzoin/THF skin protectant in order to further deter bacterial infection. Anti-mastitis compositions which include a germicide have previously been developed. For example, U.S. Pat. No. 4,891,216 discloses the incorporation of a chlorous acid/chlorine dioxide system. U.S. Pat. No. 5,529,770 discloses the incorporation of iodine as a germicide in an aqueous lactating cow barrier composition. However, both of the systems described in these patents are aqueous. The benzoin/THF skin protectant of the parent application presents unique formulation problems since it is not an aqueous system.
For example, iodine crystals will readily dissolve in tetrahydrofuran (THF) when added to the benzoin/THF skin protectant. However, upon standing, the composition shows a decrease in pH and a color change, indicating a chemical reaction between the iodine and the other ingredients of the formulation. Also, attempts to dissolve povidone iodine powder into the benzoin formulation have been unsuccessful.
It has now been discovered that certain germicidal agents can be added to the previously described benzoin/THF skin protectant to produce a stable, effective, germicidal skin protectant.
It has also been discovered that dyes can be added to the benzoin/THF skin protectant to make it easier to visualize on the skin area where it has been applied. Further, other solvents may be substituted for the THF which may in some instances significantly decrease the cost of manufacturing the benzoin skin protectant.
It is therefore a primary objective of the present invention to provide a highly adhesive, benzoin skin protectant composition which is also germicidal.
It is a further objective of the present invention to provide a germicidal benzoin skin protectant which is stable.
It is a further objective of the present invention to provide a germicidal benzoin skin protectant which is not harmful to animal skin.
It is a further objective of the present invention to provide a benzoin skin protectant which includes an indicator dye.
It is a further objective of the present invention to provide a germicidal benzoin skin protectant which is economical to manufacture.
These and other objectives will become clear from the following description of the invention.